Java Oops Quiz

22 Questions | By Srividya123 | Updated: Mar 22, 2022 | Attempts: 28972

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Popularly known as Java's object-oriented programming concepts, Oops form the backbone of java programming. Tech specialists and programmers are familiar with this but giving the quiz a short will be worthwhile in advancing your knowledge. This "Java OOPs Quiz" is designed to test your understanding of the concepts of Java OOPs. Make sure to pick the right option to get the highest score! Good Luck!

Questions and Answers

1.

HAS-A relationships are based on inheritance, rather than usage.
- A.
  
  True
- B.
  
  False
2.

Given below the sample code : 1 class Hotel { 2 public int bookings; 3 public void book() { 4 bookings++; 5 } 6 } 7 public class SuperHotel extends Hotel { 8 public void book() { 9 bookings--; 10 } 11 public void book(int size) { 12 book(); 13 super.book(); 14 bookings += size; 15 } 16 public static void main(String args[]) { 17 Hotel hotel = new Hotel(); 18 hotel.book(2); 19 System.out.print(hotel.bookings); 20 }} How can we correct the above code ? (choose all that apply)
- A.
  
  By adding argument "int size" to the method book at line number 3.
- B.
  
  By removing argument '2' at line number 18.
- C.
  
  By creating object of "SuperHotel" subclass at line 17 & calling book(2) from it at line 18
- D.
  
  No correction needed.
3.

The methods in class object are(choose four)
- A.
  
  Clone
- B.
  
  Notify
- C.
  
  Concat
- D.
  
  Wait
- E.
  
  Equals
- F.
  
  Compare
4.

Array or collection of superclass references can be used to access a mixture of superclass and subclass objects.
- A.
  
  True
- B.
  
  False
5.

Given the following sample code: public class Example5{ public float Twin(float a, float b) {... } public float Twin(float a1, float b1) { ...} } How can we correct the above code ?(choose two)
- A.
  
  By placing overriding method into subclass.
- B.
  
  By changing the name of the class.
- C.
  
  By replacing overloading from overriding.
- D.
  
  By changing the name of the arguments.
6.

At run-time, a Java program is nothing more than objects ‘talking’ to ___________.
- A.
  
  Other objects
- B.
  
  Other metods
- C.
  
  Other classes
- D.
  
  Other binders
7.

The relation between Car and Owner or BankAccount and Customer is example for
- A.
  
  Aggregation
- B.
  
  Composition
- C.
  
  Association
- D.
  
  None
8.

Aggregation is a special form of association.
- A.
  
  True
- B.
  
  False
9.

Subclassing polymorphism is sometimes called “true polymorphism”.
- A.
  
  True
- B.
  
  False
10.

Consider the below code and choose the correct output. public class Main { public int a; public long b; public void test(long b) { System.out.println("long b"); } public void test(int a) { System.out.println("int a"); } public static void main(String[] args) { Main e=new Main(); e.test(9*1000000000); } }
- A.
  
  Int a
- B.
  
  Long b
- C.
  
  Long a
- D.
  
  Error
11.

An interface cannot have an inner class.
- A.
  
  True
- B.
  
  False
12.

Polymorphism is one interface with __________.
- A.
  
  Single method
- B.
  
  Multiple methods
- C.
  
  Multiple record
- D.
  
  Single record
13.

Method overloading is done during _______.
- A.
  
  Runtime
- B.
  
  Dynamic binding
- C.
  
  Program compilation
- D.
  
  Late binding
14.

Interfaces are fast as it requires extra indirection to find corresponding method in the actual class.
- A.
  
  True
- B.
  
  False
15.

Ad hoc polymorphism is ____________.
- A.
  
  Method Overloading
- B.
  
  Method Overriding
- C.
  
  Subclassing polymorphism
- D.
  
  Dynamic binding
16.

The inheriting class cannot override the definition of existing methods by providing its own implementation.
- A.
  
  True
- B.
  
  False
17.

Consider the code below and choose the correct option. class GameShape { public void displayShape() { System.out.println("displaying shape"); } // more code } class PlayerPiece extends GameShape { public void movePiece() { System.out.println("moving game piece"); } // more code } public class TestShapes { public static void main (String[] args) { PlayerPiece shape = new PlayerPiece(); shape.displayShape(); shape.movePiece(); } }
- A.
  
  PlayingPiece class inherits the generic movePiece() method
- B.
  
  PlayingPiece class inherits the generic displayShape() method
- C.
  
  GameShape class inherits the generic displayShape() method
- D.
  
  GameShape class inherits the generic movePiece() method
18.

The two most common reasons to use inheritance are( choose 2)
- A.
  
  To promote code reuse
- B.
  
  To use abstraction
- C.
  
  To use interface
- D.
  
  To use polymorphism
19.

Examples of class are( choose 3)
- A.
  
  White
- B.
  
  Length
- C.
  
  Classroom
- D.
  
  Car
- E.
  
  Person
20.

In OO, the concept of IS-A is based on
- A.
  
  Class inheritance
- B.
  
  Interface implementation.
- C.
  
  Both
- D.
  
  None
21.

The benefits of the Object Orientation are: ( choose two )
- A.
  
  Inheritance
- B.
  
  Flexibility
- C.
  
  Maintainability
- D.
  
  Polymorphism
22.

If you don't have the access to the source code for a class, but you want to change the way a method of that class works, then could you use subclassing to do that that is to extend the "bad" class and override the method with your own better code?
- A.
  
  True
- B.
  
  False